/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.hadoop.chukwa.datacollection.adaptor;
  
  import java.io.IOException;
  import java.net.*;
  import java.util.Arrays;
  import org.apache.hadoop.chukwa.*;
  import org.apache.log4j.Logger;
  
  public class UDPAdaptor extends AbstractAdaptor {
  
    static Logger log = Logger.getLogger(UDPAdaptor.class);
    
    int portno;
    DatagramSocket ds;
    volatile boolean running = true;
    volatile long bytesReceived = 0;
    String source;
    
    class ListenThread extends Thread {
      public void run() {
        log.info("UDP adaptor " + adaptorID + " started on port " + portno + " offset =" + bytesReceived);
        byte[] buf = new byte[65535];
        DatagramPacket dp = new DatagramPacket(buf, buf.length);
        try {
          while(running) {
            ds.receive(dp);
            send(buf, dp);
          }
        } catch(Exception e) {
          if(running)
            log.error("can't read UDP messages in " + adaptorID, e);
        }
      }
    }
    ListenThread lt;
  
    public void send(byte[] buf, DatagramPacket dp) throws InterruptedException, IOException {
      byte[] trimmedBuf =  Arrays.copyOf(buf, dp.getLength());
      bytesReceived += trimmedBuf.length;
      Chunk c = new ChunkImpl(type, source, bytesReceived, trimmedBuf, UDPAdaptor.this);
      dest.add(c);
    }
    
    @Override
    public String parseArgs(String s) {
      portno = Integer.parseInt(s);
      source = "udp:"+portno;
      return s;
    }
  
    @Override
    public void start(long offset) throws AdaptorException {
      try {
        bytesReceived = offset;
        ds = new DatagramSocket(portno);
        portno = ds.getLocalPort();
        lt = new ListenThread();
        lt.start();
      } catch(Exception e) {
        throw new AdaptorException(e);
      }
    }
  
    @Override
    public String getCurrentStatus() {
      return type + " " + portno;
    }
  
    @Override
    public long shutdown(AdaptorShutdownPolicy shutdownPolicy)
        throws AdaptorException {
      try {
        running = false;
        ds.close();
  //      if(shutdownPolicy == AdaptorShutdownPolicy.GRACEFULLY)
          lt.join();
      } catch(InterruptedException e) {}
      return bytesReceived;
    }
  
  }